* Changed `Load` to `Unmarshal`
* made `Marshal` and `Unmarshal` into methods of `COF`
* added `New` function which creates a new, empty COF instance
* added helper functions `Marshal` and `Unmarshal`
* Changed `StreamReader.ReadBytes` to account for edge case of reading 0
bytes (this was returning an error when it should not have)
* added really simple unit tests for COF
*`StreamReader.Read` methods now return errors
The other edits in this commit are related to cleaning up lint errors
caused by the changes to StreamReader
* d2player/inventory.go: fixed gocyclo error, broke up render method to smaller methods
* d2client/game_client.go: suppressing gocyclo error for OnPacketReceived, doesnt make sense to split
* d2remoteclient/remote_client_connection.go: suppressing gocyclo error for decodeToPacket, doesnt make sense to split
* d2dcc/dcc_direction.go: suppressing gocyclo error in generateFrames
* suppressing the magic number lint errors in mapgen, it will get a heavy refactor soon, hopefully...
* adding string token constants for SkillClass
* adding panic on error to left/right skill select render
* fixed cuddle lint error
* fixed unnecessary conversion, unused func param lint errors in dcc_animation.go
* adding comment for skill class tokens
* fixed typo in comment
* removed unused parameter in dcc/dc6 animations
* supress warning about Object.setMode always being passed direction value of 0
* fixed all invalid golint directives
* fixed a couple gocritic lint errors
* removed the rest of the magic number errors from d2game
* hotfix for bug i added in map engine test
* removed all TODO's in project, made issues on github for each one
